Test Widely Denounced, Including in Beijing

By

Evan Ramstad And

Brian Spegele

Updated Feb. 12, 2013 12:29 p.m. ET

SEOUL—North Korea's explosion of a nuclear device on Tuesday drew withering international criticism, with the U.N. Security Council calling the blast a "clear threat to international peace and security" and pledging action.

After three weeks of warnings and bombastic buildup, North Korea exploded the device—its third test in a weapons program that dates back to the 1960s—shortly before noon local time inside the same...